---
title: "Version 1.5.0"
description: "Complete MCP Server SDK with routing, logging, and developer tools"
icon: "sparkles"
og:image: "https://cdn.mcp-use.com/release1.5.0.png"
---

<Card img="https://cdn.mcp-use.com/release1.5.0.png" title="Release 1.5.0" href="https://github.com/mcp-use/mcp-use/releases/tag/python-v1.5.0">
  We've introduced a **complete MCP Server SDK**, enabling you to build production-ready MCP servers with routing, advanced logging, inspector integration, and multiple transport protocols.
</Card>

## Major Changes

### Complete MCP Server SDK

Build powerful MCP servers with a comprehensive SDK that rivals FastMCP while providing unique capabilities for production deployments.

**Key Components:**

#### MCPServer - Production-Ready Server Class
Built on top of FastMCP with significant enhancements for production use:

```python
from mcp_use.server import MCPServer

server = MCPServer(
    name="my-awesome-server",
    version="1.0.0",
    instructions="A production-ready MCP server",
    debug=True,  # Enable development tools
    pretty_print_jsonrpc=True,  # Beautiful JSON-RPC logs
)

@server.tool()
def calculate(expression: str) -> float:
    """Evaluate a mathematical expression."""
    return eval(expression)

# Run with multiple transport options
server.run(
    transport="streamable-http",  # or "stdio", "sse"
    host="0.0.0.0",
    port=8000,
    reload=True  # Auto-reload on code changes
)
```

**Features:**
- Multiple transport protocols: stdio, streamable-http, SSE
- Integrated development tools and inspector
- Advanced logging with customizable formats
- Production-ready with signal handling
- FastMCP compatibility layer

#### MCPRouter - Modular Server Organization
Organize your MCP server into reusable modules, similar to FastAPI's APIRouter:

```python
from mcp_use.server import MCPServer, MCPRouter

# routes/math.py
math_router = MCPRouter()

@math_router.tool()
def add(a: float, b: float) -> float:
    """Add two numbers."""
    return a + b

@math_router.tool()
def multiply(a: float, b: float) -> float:
    """Multiply two numbers."""
    return a * b

# routes/weather.py
weather_router = MCPRouter()

@weather_router.resource(uri="weather://current/{city}")
def get_weather(city: str) -> str:
    """Get current weather for a city."""
    return f"Weather data for {city}"

# main.py
server = MCPServer(name="multi-module-server")
server.include_router(math_router, prefix="math")  # Tools: math_add, math_multiply
server.include_router(weather_router, prefix="weather")
server.include_router(admin_router, enabled=False)  # Conditionally disable routers
```

**Features:**
- Clean separation of concerns
- Reusable modules across projects
- Optional prefixing for namespacing
- Conditional router enabling/disabling
- Support for tools, resources, and prompts

#### Enhanced Context with Advanced Capabilities
Extended context object with powerful server-side features:

```python
from mcp_use.server import MCPServer, Context

server = MCPServer(name="context-demo")

@server.tool()
async def smart_search(query: str, ctx: Context) -> str:
    """Intelligent search with LLM refinement."""
    # Sampling: Request LLM assistance from the client
    result = await ctx.sample(
        messages=f"Refine this search query: {query}",
        max_tokens=100,
        temperature=0.7,
        model_preferences={"hints": [{"name": "claude-3-5-sonnet"}]}
    )
    refined_query = result.content.text
    
    # Elicitation: Get structured input from user
    from dataclasses import dataclass
    
    @dataclass
    class SearchFilters:
        date_range: str
        categories: list[str]
        max_results: int = 10
    
    filters = await ctx.elicit(
        message="Please specify search filters",
        schema=SearchFilters  # Supports both Pydantic and dataclasses
    )
    
    # Perform search with refined query and filters...
    return f"Results for '{refined_query}' with filters: {filters.data}"

@server.tool()
async def add_new_tool(name: str, ctx: Context) -> str:
    """Dynamically register a new tool."""
    # Notify clients about tool list changes
    await ctx.send_tool_list_changed()
    return f"Added tool: {name}"

@server.tool()
async def get_request_info(ctx: Context) -> dict:
    """Access HTTP request details."""
    request = ctx.get_http_request()
    if request:
        return {
            "method": request.method,
            "url": str(request.url),
            "headers": dict(request.headers)
        }
    return {"transport": "stdio"}
```

**Context Features:**
- `sample()`: Client-side LLM sampling with model preferences
- `elicit()`: Structured user input with Pydantic or dataclass schemas
- `send_tool_list_changed()`: Dynamic tool registration notifications
- `send_resource_list_changed()`: Resource update notifications
- `send_prompt_list_changed()`: Prompt update notifications
- `get_http_request()`: Access underlying HTTP request (streamable-http only)

#### Advanced Logging System
Production-grade logging with beautiful formatting and debugging tools:

**Features:**
- Customizable log formats with color-coded output
- JSON-RPC request/response logging
- Session ID tracking across requests
- Request/response size monitoring
- Configurable debug levels (0=production, 1=debug, 2=verbose)
- Middleware-based architecture for extensibility

**Debug Levels:**
```bash
# Production: Clean logs only
DEBUG=0 python server.py

# Debug: Clean logs + dev routes (/docs, /inspector, /openmcp.json)
DEBUG=1 python server.py

# Verbose: Everything + JSON-RPC logging with pretty printing
DEBUG=2 python server.py
```

#### Built-in Development Tools

**Inspector Integration:**
- Auto-populated inspector at `/inspector`
- Real-time tool testing
- Request/response inspection
- Session management

**Documentation UI:**
- Auto-generated docs at `/docs`
- Interactive API explorer
- Tool/resource/prompt documentation

**OpenMCP Configuration:**
- Standard OpenMCP config at `/openmcp.json`
- Easy integration with MCP clients
- Auto-discovery support

#### Multiple Transport Protocols

```python
# Stdio - Traditional MCP transport
server.run(transport="stdio")

# Streamable HTTP - Recommended for production
server.run(
    transport="streamable-http",
    host="0.0.0.0",
    port=8000
)

# SSE - Server-Sent Events (deprecated, use streamable-http)
server.run(
    transport="sse",
    host="127.0.0.1",
    port=8000
)
```

**Transport Comparison:**
- `stdio`: Best for local CLI tools and desktop apps
- `streamable-http`: Recommended for web services and cloud deployments
- `sse`: Legacy support (deprecated in favor of streamable-http)

#### FastMCP Migration Path

Seamless migration from FastMCP with compatibility exports:

```python
# Old FastMCP code
from fastmcp import FastMCP

server = FastMCP(name="my-server")

# New mcp-use code - drop-in replacement
from mcp_use.server import FastMCP  # Compatibility alias

server = FastMCP(name="my-server")  # Works identically

# Or use enhanced MCPServer for new features
from mcp_use.server import MCPServer

server = MCPServer(name="my-server")  # Recommended
```

See [FastMCP compatibility guide](/python/server/compatibility) for migration details.

## Enhancements

### Middleware Parameter Mutation

Middleware can now modify request parameters, with changes properly propagated:

```python
from mcp_use.client import MCPClient, Middleware, MiddlewareContext

class ParameterEnrichmentMiddleware(Middleware):
    async def process_request(self, context: MiddlewareContext):
        # Middleware can now modify context.params
        if context.request_type == "call_tool":
            # Add/modify parameters
            context.params["enriched"] = True
            context.params["timestamp"] = time.time()
        
        # Changes are automatically propagated to the tool call
        return await context.next()

client = MCPClient(
    config={"mcpServers": {...}},
    middleware=[ParameterEnrichmentMiddleware()]
)
```

**Changes:**
- Middleware parameter modifications are now preserved
- `context.params` can be mutated and changes propagate
- Improved middleware documentation with examples

See [PR #522](https://github.com/mcp-use/mcp-use/pull/522) for details.

### Enhanced Sampling & Elicitation

Server-side support for advanced MCP protocols:

**Sampling:**
```python
@server.tool()
async def intelligent_tool(query: str, ctx: Context) -> str:
    # Request LLM assistance from the client
    response = await ctx.sample(
        messages=[
            "You are a helpful assistant",
            {"role": "user", "content": query}
        ],
        max_tokens=500,
        temperature=0.8,
        model_preferences={"hints": [{"name": "claude-3-5-sonnet"}]}
    )
    return response.content.text
```

**Elicitation:**
```python
@server.tool()
async def structured_input(ctx: Context) -> dict:
    # Get structured user input
    result = await ctx.elicit(
        message="Please provide task details",
        schema=TaskSchema
    )
    
    if result.action == "accept":
        return result.data.model_dump()
    else:
        return {"cancelled": True}
```

### Tool Enable/Disable Support

Dynamic tool management during runtime:

```python
@server.tool()
async def toggle_feature(feature: str, enabled: bool, ctx: Context) -> str:
    # Enable or disable tools dynamically
    if enabled:
        # Register new tool
        pass
    else:
        # Unregister tool
        pass
    
    # Notify clients
    await ctx.send_tool_list_changed()
    return f"Feature {feature} {'enabled' if enabled else 'disabled'}"
```

## Code Quality

### Type Checking with Ty

Introduced **ty** as the official type checker for better type safety:

```bash
# Run type checking
ty check

# Pre-commit integration
git commit  # Automatically runs ty on staged files
```

**Benefits:**
- Strict type checking for improved code quality
- Pre-commit integration with prek
- Configured to ignore certain patterns for flexibility

### Pre-commit Hooks with Prek

Standardized pre-commit workflow with **prek**:

```bash
# Install pre-commit hooks
prek install

# Run on all files
prek run --all-files
```

**Hooks:**
- Type checking with ty
- Code formatting with ruff
- Import sorting
- Trailing whitespace removal

### Refactored Test Suite

Complete test reorganization for better maintainability:

**Structure:**
```
tests/
├── client/           # Client-side tests
│   ├── primitives/   # MCP primitives (tools, resources, prompts)
│   ├── transports/   # Transport protocols
│   └── others/       # Other client features
└── server/           # Server-side integration tests (future)
```

**Improvements:**
- Tests now use MCPServer instead of external servers
- Removed dependency on FastMCP test servers
- Better test isolation
- Clearer test organization

### Ruff Configuration

Moved Ruff configuration from separate file to pyproject.toml:

```toml
[tool.ruff]
line-length = 120
target-version = "py311"

[tool.ruff.lint]
select = ["E", "F", "I", "W", "B", "UP"]
```

**Benefits:**
- Single configuration file
- Consistent with Python ecosystem standards
- Easier project setup

## Documentation

### New Server Documentation

Comprehensive documentation for the new server SDK:

- [Server Overview](/python/server/index) - Introduction and architecture
- [Router Guide](/python/server/router) - Modular server organization
- [Logging System](/python/server/logging) - Production logging setup
- [Running Servers](/python/server/running) - Deployment guide
- [Inspector Integration](/python/server/inspector) - Debugging tools
- [FastMCP Migration](/python/server/compatibility) - Migration guide
- [Sampling](/python/server/sampling) - Client LLM requests
- [Elicitation](/python/server/elicitation) - Structured user input
- [Notifications](/python/server/notifications) - Dynamic updates

### Updated Examples

New example servers showcasing features:

- `context_example.py` - Context features demo
- `fastmcp_example.py` - FastMCP compatibility
- `fastmcp2_example.py` - Advanced FastMCP patterns
- `fmcp_use_server_example.py` - Full-featured server

### API Reference

Auto-generated API documentation for all new modules:

- `mcp_use.server.server` - MCPServer class
- `mcp_use.server.router` - MCPRouter class
- `mcp_use.server.context` - Enhanced Context
- `mcp_use.server.logging` - Logging components
- `mcp_use.server.runner` - Server runner
- `mcp_use.server.types` - Type definitions
- `mcp_use.server.utils` - Utility functions

## Breaking Changes

None - all changes are backward compatible. Existing client code continues to work without modifications.

## Migration Guide

### Starting a New Server

```python
from mcp_use.server import MCPServer

server = MCPServer(
    name="my-server",
    version="1.0.0",
    debug=True  # Enable dev tools during development
)

@server.tool()
def my_tool(arg: str) -> str:
    return f"Result: {arg}"

if __name__ == "__main__":
    server.run(transport="streamable-http", port=8000)
```

### Migrating from FastMCP

Replace imports and enjoy enhanced features:

```python
# Before
from fastmcp import FastMCP
server = FastMCP(name="my-server")

# After - Option 1: Compatibility mode
from mcp_use.server import FastMCP
server = FastMCP(name="my-server")

# After - Option 2: Full features (recommended)
from mcp_use.server import MCPServer
server = MCPServer(name="my-server", debug=True)
```

### Organizing with Routers

Split large servers into modules:

```python
# routes/database.py
from mcp_use.server import MCPRouter

db_router = MCPRouter()

@db_router.tool()
def query(sql: str) -> list:
    return []

# main.py
from mcp_use.server import MCPServer
from routes.database import db_router

server = MCPServer(name="my-server")
server.include_router(db_router, prefix="db")
```

### Enabling Advanced Features

```python
from mcp_use.server import MCPServer, Context

server = MCPServer(name="advanced-server")

@server.tool()
async def advanced_tool(query: str, ctx: Context) -> str:
    # Use sampling
    result = await ctx.sample(messages=query)
    
    # Send notifications
    await ctx.send_tool_list_changed()
    
    # Access HTTP request
    request = ctx.get_http_request()
    
    return result.content.text
```

## Dependencies

### Updated Requirements

```toml
mcp>=1.10.0  # Updated for latest MCP features
pydantic>=2.11.0  # Enhanced schema support
```

### New Development Tools

```toml
[project.optional-dependencies]
dev = [
    "prek>=0.2.0",  # Pre-commit framework
    "ty>=0.0.1a7",  # Type checker
]
```

## Contributors

Thank you to all contributors who made this release possible:

- Pietro Zullo (@pietrozullo)
- Vladimir Krasnoselskikh (@v-krasnoselskikh-im)
- Vincenzo Reina (@renvins)
- Enrico Toniato (@tonxxd)

## Statistics

- **Total Commits:** 30+ (Python-specific)
- **Files Changed:** 106
- **Lines Added:** 5,818+
- **Lines Removed:** 4,402+
- **New Modules:** 15+
- **New Examples:** 4
- **New Documentation Pages:** 10+

---

For full changelog and commit history, see the [commit log](https://github.com/mcp-use/mcp-use/compare/e76f5e76...be9942a4).

